During the mechanical cleaning of waste water in settling tanks or other devices, it is necessary, aside from the impurities settled as sediments to also remove floating matter accumulated on the surface. It is common to separate the floating matter from the surface of the waste water through a continuous pumping off or through a mechanical removal thereof. Such a method for the removal and the collection of such floating matter requires considerable expense. The floating matter must be pumped off or removed in any other manner from the entire surface of the waste water in the settling tank independent of their structure so that the associated suction or conveying devices must be guided accordingly, whereby in most cases attention must in addition be paid to the removers required in these settling tanks and their movement, which also just like the suction or conveying devices must be continuously moved. Large amounts of water are also pumped in with this method.
The basic purpose of the invention is therefore to carry out such a method identified in detail above in such a manner that the building expense is kept low and in particular a transfer of the floating matter is made possible in a simple manner and with very little water also in the drainage container.
The purpose is attained according to the invention in such a manner that the floating matter is conveyed by means of a worm conveyor into an intermediate container submerged into the settling tank and thereby displace the waste water existing therein through an opening arranged in the bottom area, and the conveyed matter accumulated in the intermediate container is pumped off as needed time-dependently or fill-dependently.
The intermediate container is thus connected as a buffer between a continuously operated removal of the floating matter from the surface of the waste water and a discontinuous evacuation determined by the amount of the accumulated floating matter.
The floating matter is removed from the surface in a wide front by the worm conveyor when same is moved during the conveying of the floating matter transversely to its longitudinally extending axle determined by the conveying direction along the surface of the waste water. The worm conveyor is thereby rotated advantageously such that same moves out of the water on the side where the floating matter is supplied. This results in an extremely effective removal of the floating matter. It is also conceivable to arrange the worm conveyor stationarily and to feed the floating matter to same by means of a suitable removing mechanism. Stationary worm conveyors can be used in the case of nonround tanks.
Thus, floating matter flows toward the worm conveyor over its effective length, and the floating matter is moved in direction of the longitudinal axle (conveying direction) to the end of the worm conveyor by the helically extending element rotating about its longitudinal axle, assuming a suitable structural design, as will be discussed below.
A funnel is advantageously arranged in the intermediate container closely below the waste water surface, which funnel fills out advantageously approximately the entire cross section of the intermediate container. This funnel is connected to the suction opening of a pump.
In order to support a pumping off through the funnel it is advantageous when little water flows from the settling tank through the bottom opening into the intermediate container. The amount of water can thereby be regulated by a bottom valve.
The floating matter resting on the waste water is seized at an optimum by the worm conveyor and is moved into the intermediate container, when the worm conveyor consisting of a worm shaft supported in the intermediate container and a helically extending element is arranged on the surface of the waste water and extends parallel thereto, particularly effectively due to the fact that since the worm conveyor is guided in height above the waste water such that the worm shaft, being thereby approximately tangent with the surface of the waste water, forms a barrier for the floating matter. The height guiding can thereby be done manually or by a level control; however, it can also be adjusted to a fixed value when the surface of the waste water itself is regulated in height. The inventive guiding of the worm conveyor assures that all floating matter reaches into the area of the helically extending member thereof and not to the discharge side of the worm conveyor when they are hindered during conveying by the helically extending member thereof from leaving the worm conveyor as will yet be discussed below.
The respective pumping off of the floating matter from the intermediate container occurs either in dependency of the amount of the fed-in conveyed matter or time-dependently.
The method is advantageously carried out by means of a floating matter removing device of the invention, in which the intermediate container is provided at one end of the worm conveyor which lies in its conveying direction so that the worm conveyor is utilized over its entire length. It is thereby advantageous when a drive motor for the worm conveyor is provided on the intermediate container (outside of the waste water) so that no movable inbetween links are necessary, instead all three building groups of the worm conveyor, of the intermediate container and of the drive motor form a structural unit and can be fixedly connected with one another at the latest during a mounting thereof on the settling tank.
It is advantageous for such a fixed association when a pipe-shaped closed, short worm housing for the worm conveyor is provided on the intermediate container, the length of which corresponds, for example, at least to the single, advantageously, however, to three times the outside diameter of the worm conveyor. The effect of the worm housing can thereby be still further improved by the inside diameter of the worm housing exceeding the outside diameter of the worm conveyor only by so much that a feeding back of the conveyed matter against the conveying direction is essentially impossible.
A safe guiding of the worm conveyor on the housing of the intermediate container is guaranteed in this manner without that the free or open lateral accessibility of the worm conveyor for receiving the arriving floating matter would be improperly limited, and on the other hand it can be assured with simple structural measures that the conveyed matter can be moved only in a conveying direction even in the direct vicinity of the intermediate container.
In particular it is especially place saving when the drive motor is provided on the part of the intermediate container which projects from the waste water, in particular when the worm shaft is thereby guided through the walls of the intermediate container which in this manner are utilized for supporting the worm conveyor.
In order to be able to mix and discharge pure waste water with the conveyed matter in the intermediate container, a feed valve can be provided in a simple manner on the intermediate container and preferably in the area of the container bottom, through which valve the inside of the intermediate container can be connected to the waste water in the settling tank. It is thereby advantageous when the feed valve can be operated by a preferably manually operable adjusting device leading out of the settling tank so that the admixing of waste water can be controlled. A mechanical adjusting device, for example, in the form of an adjusting rod is thereby sufficient.
A particularly preferred embodiment of the cleaning device of the invention provides a conveyor pump in the intermediate container for conveying the conveyed matter through the conveyor line so that with an encapsulated, efficient and space-saving pressure pump the transfer of the conveyed matter, which as a rule can be pumped easily, from the intermediate container can be accomplished.
The operation of the arrangement of the invention demands that the helically extending member is open over its entire length on the oncoming flow side so that the floating matter moves into its operating area. The helically extending member can provide a perfect conveying operation even when a discharge side baffle plate is provided on the worm conveyor over the entire length thereof on its side not facing the oncoming waste water. The baffle plate accordingly forms a rudiment of a worm housing; it is advantageous when it partially underpins the worm conveyor, preferably a small distance from the helically extending member. A worm conveyor constructed in this form operates highly efficiently and completely removes the floating matter lying on the waste water.
However, the worm conveyor is in a particularly preferred design mounted on a remover, which is mostly at any rate provided on the settling tank and is movable over the surface of the waste water, so that no additional guiding and driving mechanisms are needed. The removing device can be mounted in particular to the remover since several fastening mountings are provided for the worm conveyor on the remover. Also the baffle plate is then advantageously fixed to these mountings and can in this manner be mounted precisely fitting with respect to the helically extending member. The entire movement of the worm conveyor over the settling tank is thus coupled to the remover. As a result, the general very high required output is also in addition sufficient for moving the removing device.
Such an energy-saving design is also not limited to a certain geometric form of the setting tank; the arrangement is, in spite of this, particularly easily realizable when a circularly shaped settling tank with a rotating remover is provided.
The surface of the waste water is completely cleansed of floating matter in the settling tank in spite of the built-ins needed therein (support for the remover, intermediate container) when the worm conveyor has guide plates or guide rails at one or both ends, which rails slide along during the movement of the worm conveyor on the stationary walls of the settling tank in such a manner that the waste water is thereby supplied in the area of its surface to the worm conveyor, whereby a guide plate/guide rail can cover the intermediate container in oncoming flow direction of the waste water.
The method of the invention enables in connection with the associated removing device a cleaning of the waste water using very little energy, which is limited to the drive motor for the conveying operation of the worm conveyor and the evacuation of the intermediate container. It is particularly remarkable that the containers used for removing the conveyed matter can be set up at any desired spot outside and in the vicinity of the settling tank, and the remover together with the removing device can always be stopped at the same point so that also the needed system for pumping off and transferring of the conveyed matter can be designed stationarily.